(1) Field of the Invention
The present invention generally relates to ink-jet heads, and more particularly to an ink-jet head of a color printer which is used for various systems including copiers, facsimiles, computers, wordprocessors or the like.
(2) Description of the Related Art
Generally, an ink-jet head 10, as shown in FIG. 10A, has a yellow segment chip 12, a magenta segment chip 13, a cyan segment chip 14 and a black segment chip 15 which are held by a holder 11. These segment chips are arrayed in parallel in the holder 11 in this order. In FIG. 10A, "X" indicates a main scanning direction in which the ink-jet head 10 is moved, and "Y" indicates a sub-scanning direction in which a sheet of paper is delivered.
The segment chips 12, 13, 14 and 15 respectively include nozzles 12a, 13a, 14a and 15a. The nozzles of two of the segment chips 12-15 are spaced apart at a given distance in the main scanning direction X, and the nozzles for each of the segment chips 12-15 are spaced apart at a given distance in the sub-scanning direction Y. In FIG. 10A, "S" indicates a pitch between the nozzles of two of the segment chips 12 through 15 in the main scanning direction X.
FIG. 10B is an enlarged view of a portion "A" of the ink-jet head 10 of FIG. 10A. As shown in FIG. 10B, the arrangement of the nozzles of one of the segment chips 12-15 deviates from the arrangement of the nozzles of another segment chip with a given pitch in the sub-scanning direction Y. In FIG. 10B, "Q" indicates a pitch between the nozzles of the segment chips 12 through 15 in the sub-scanning direction Y.
If the ink-jet head 10 of the above-mentioned type is designed to provide a resolution of about 300 dpi (dots per inch), in order to produce an ink-jet head having this resolution, it is necessary to join together the holder 11 and the segment chips 12-15 with the pitch S being set within a tolerance of .+-.5 .mu.m and the pitch Q being set within a tolerance of .+-.5 .mu.m. Thus, the volume production of the ink-jet head 10 requires delicate assembly operations and accurate adjustments.
Therefore, in order to attain volume production, it is desired to provide a structure of an ink-jet head which provides a required level of accuracy for positioning the components at a low cost while requiring only simple assembly operations.
As disclosed in Japanese Laid-Open Patent Application No. 7-40531, a conventional method of production of an ink-jet head uses an automatic gripper and a positioning block. The ink-jet head has segment chips held by a holder, similar to the ink-jet head 10 of FIG. 10A. When the ink-jet head is assembled, the holder is fixed to the positioning block, and the automatic gripper holds and moves the segment chip relative to the positioning block. The segment chips are set by the automatic gripper at given locations within the holder. At this time, base plates attached to the segment chips are placed into grooves of the holders. The base plates attached to the segment chips are then bonded to the holder using adhesive agent.
In the conventional method of the above-mentioned publication, the structure of the ink-jet head is not adequate to provide accurate positioning of the nozzles of the segment chips on the holder. The base plates are bonded to the holder by the adhesive agent, and the pitch between the nozzles of the segment chips held on the holder may be affected by a curing condition of the adhesive agent. Further, the segment chips are fixed to the holder through the base plates, which may cause a deviation of the positions of the segment chips from the accurate positions of the nozzles. Therefore, it is difficult for the conventional method to provide accurate positioning of the nozzles of the segment chips on the holder.
Further, the conventional method of the above-mentioned publication has to use the automatic gripper to place the segment chips on the holder, and it is difficult for the conventional method to produce the ink-jet head at a low cost.